Coming off the third losing season in the previous four years, the Minnesota Vikings have plenty to prove to avoid another last-place finish in the NFC North. Free agency additions Captain Munnerlyn and Linval Joseph figure to plug major holes in the defense, while offensive coordinator Norv Turner and rookie Teddy Bridgewater aim to take Adrian Peterson and the offense to new heights.

But there is a crop of familiar faces who will be asked to take significant leaps in 2014.

As we prepare for the first training camp practice on Friday, here's a list of Vikings players with the most to prove this season:

1. DE Everson Griffen -- After offseason musical chairs, Griffen is now sitting in the throne. He takes Jared Allen's place, but he'll play a drastically different role than the pure pass rusher. Griffen is now the 10th-highest paid defensive end in the NFL (now higher than Allen) and for the first time in his career he'll be asked to play both the run and pass on every down. Griffen has proved capable as a fill-in, but his versatility and reliability are crucial for how creative Mike Zimmer can be on defense in his first year. A continued PSA: Don't relate Griffen's future sack numbers to his contract (or for any DE). Only one defensive end, Michael Johnson in 2012, had 10+ sacks for Zimmer in his six years with the Bengals. They'll want Griffen to get after the quarterback at times, but he'll often be looking to defend the run first.

2. DT Sharrif Floyd -- After the Vikings' loss at Chicago last season, I remember Kevin Williams motioning to Floyd, saying something to the effect of 'You getting both arms up? Can't just keep using one.' As Floyd enters his second year, he won't have Williams' wisdom by his side to advise him on pass deflections. The Vikings have a new three-technique defensive tackle for the first time since 2003 and the burden is on Floyd to produce, even though he played fewer than 40 percent of snaps as a rookie. When Floyd was derailed by a preseason knee injury, the Vikings had to rely on Williams more than they intended in 2013. Now, the fallback is Tom Johnson. As a starter, he'll be asked to play a much larger role -- one that could make him a lot of money. Zimmer designs to his players' strengths, which for Floyd resembles Geno Atkins, who has 26 sacks since 2011 in Cincinnati.

3. S Jamarca Sanford-- Two of the top four tacklers on the Bengals defense last season were safeties. Whoever starts alongside Harrison Smith this season will be asked to play at the line of scrimmage, force turnovers and make tackles upfield. Both Smith and Sanford are undergoing a shift from how they previously played the position in a Tampa-2 defense, though Sanford faces more competition to hold onto his spot this season.

The Vikings restructured Sanford's contract after he started 41 games with seven forced fumbles since 2011. His competition is particularly stiff this time around as Minnesota added Kurt Coleman through free agency, re-signed Sendejo last season and drafted Antone Exum in May. Robert Blanton saw first-team reps when Sanford was sidelined with an injury this spring and now Sanford finds himself in one of the more crowded positions on the roster. He is a free agent in 2015.

4. TE Kyle Rudolph -- Changes continue at Winter Park and that includes Rudolph, who has yet to have a 100-yard receiving game in the NFL. Though he's been voted to a Pro Bowl, Rudolph has mostly been known for his effective run blocking. That should change under Turner, who has championed some of the NFL's best pass-catching tight ends in his stops across the league. Coming off a broken foot and in a contract year, Rudolph shed 15 pounds to prepare for this season as he figures to run more routes and become a focal point of the Vikings' pass attack.5. CB Josh Robinson -- Robinson is back on the outside after an unpleasant experiment as the nickel corner last season. He's taken the majority of snaps as the third cornerback in nickel packages, as Munnerlyn shifts into the inside, and will be challenged by a crop of young talent for that spot. The Vikings added Derek Cox, drafted Jabari Price and Kendall James and still have the likes of Shaun Prater, Robert Steeples, Marcus Sherels and Julian Posey competing for final roster spots at the position. Robinson is returning from a fractured sternum he suffered in November last season and will be held to a high standard as Zimmer's defense never ranked below 14th in the league in either passing yards or touchdowns allowed in six seasons with Cincinnati.

6. LB Jasper Brinkley -- Brinkley played just 210 snaps last season as he was marred by injuries. Now that he's reunited with the Vikings, Brinkley has been running with the first-team defense as the middle linebacker since he walked back through the doors at Winter Park. He seemed enthusiastic to be playing a different role than his previous campaign in Minnesota, but this time he'll be pressured by young talent in Audie Cole and Michael Mauti. Brinkley started 15 games for Minnesota in 2012 and will have to prove his year in Arizona was an anomaly to avoid another carousel year at middle linebacker. Chad Greenway has also taken snaps in the middle and it'll be interesting to see if/where Brinkley is involved in sub or nickel packages with Greenway and Anthony Barr as options.

7. WR Jarius Wright -- In spurts, Jarius Wright has shown the ability to be a successful slot receiver in the NFL. However, as the Vikings wrestle with their quarterback situation, Wright and his fellow receivers suffer. He averaged just 27 receiving yards per game last season. With Turner at the controls and Christian Ponder likely out of the picture, Wright should expect a steadier workload on Sundays in his third year. The Vikings are relatively deep at the receiver position despite not drafting one in May. Though he shouldn't have to worry about a roster spot, Wright is among a host of slot receivers at training camp, along with former Cleveland receiver Josh Cooper, Kain Colter, Adam Thielen and Erik Lora.